The present invention relates broadly to rotary-type internal combustion engines and, more particularly, to a vane-type rotary internal combustion engine having internal, post compression magazines.
Rotary engines are engines with a working chamber whose volume is varied by revolving two or more elements with respect to one another. Rotary engines offer advantages over piston engines in that the center of gravity of the moving power output member of the reciprocating engine oscillates in a straight line while that of the rotary engine moves in one continuous circular motion. For a vehicular application, this has the advantage of smooth operation when compared to piston engines.
Modern rotary engines include a stationary housing with an internal rotor which may be moved in planetary motion within the housing. In the familiar Wankel engine, the rotor has the shape of a triangle with slightly rounded sides and rotates within a chamber formed as a "figure 8." The tips of the rotor follow the outline of the internal housing to form three working chambers which move around the housing with the rotor. As the rotor rotates, the gap between the flanks of the rotor and the wall of the housing vary cyclically, expanding and contracting to provide the four strokes of a four-cycle engine. Seals are provided at the tips of the rotor to separate the three chambers formed between the rotor and the housing.
Because each flank of the rotor acts effectively as a piston in a reciprocating engine, operation and construction of a typical rotary engine may be understood by considering only one flank of the rotor and its motion. Inlet and exhaust ports are provided at the appropriate stages and movement of the rotor carries the combustion volume over the ports.
Shaft speed in a rotary engine is typically very high but this may be achieved because of the absence of reciprocating parts. On the downside, the orbital motion of the rotor may produce out of balance loads yet these are easily counterbalanced. As will be seen, another solution to the loading due to the orbital rotor is the use of a round rotor with moving vanes. Moving vane-type rotary engines are disclosed in Kelly U.S. Pat. No. 3,452,725, Chisholm U.S. Pat. No. 3,929,105 and Hunter U.S. Pat. No. 3,951,112. In each of these patents, a round rotor is used in an eccentric rotor chamber with a plurality of vanes which are configured to move inwardly and outwardly of compartments contained within the rotors to provide the variable volume working chamber while avoiding the loads imposed by orbital rotors.
Other advantages of rotary engines include fewer moving parts, including the elimination of a valve train and as a result, the engines are typically compact.
One of the problems with rotary engines was disclosed early in their development and is caused by the shape of the combustion chamber formed between the housing and the rotor. Such a chamber is long and narrow with a large surface area for its volume which is not particularly conducive to flame propagation. These problems are exacerbated by movement of the mixture as the rotor rotates. In addition, the shape is capable of producing a high quenching action which tends to quench the flame at an early stage in the cycle resulting in dirty exhaust gases, thick with hydrocarbons.
Enhancements have been made in rotary engine design to increase combustion efficiency. Multiple inlet ports which are progressively brought into action as the power increases, direct fuel injection and the use of multiple spark plugs have enhanced combustion efficiency. Nevertheless, areas exist in rotary engine development for power enhancement as well as increased combustion efficiency.